1. Field of the Invention
The present invention relates to orthopaedic implants.
2. Description of the Related Art
It is well-known to implant orthopaedic implants into a patient's body to attempt to restore musculoskeletal function that the patient has lost or damaged due to injury or disease. Many orthopaedic implants, for example, are meant to replace bone tissue that has failed to heal correctly or cannot be naturally repaired by the patient's body. Such known orthopaedic implants can include femoral knee implants, hip implants, glenoid implants, etc.
When implanting an orthopaedic implant, it is important that the orthopaedic implant is firmly anchored (fixated) in the body. Without being firmly fixated, there is a significant risk that the implant will loosen due to movement of the surrounding anatomy, leading to implant failure and potentially more damage to the surrounding anatomy of the patient. To fixate implants in the body, traditionally an adhesive compound, known as bone cement, was used in order to provide temporary fixation before the material of the implant was integrated in the body to permanently fixate the implant.
One known issue with bone cement is that the cement substance is difficult to work with during surgery. Bone cement has a consistency very similar to normal cement and putties, which makes the bone cement difficult to remove from areas where it is not desired. If the incorrectly placed bone cement is not adequately removed, the bone cement can damage the anatomy adjacent to the implant during normal movement. To lessen the risk of this occurring, a surgeon might opt to use less bone cement to temporarily fixate the implant, but lessening the amount of bone cement used presents the risk of not using enough bone cement and not properly fixating the implant.
An alternative to using bone cement is using a fixation device, such as a bone pin or screw, that connect the implant to surrounding bone tissue. Such fixation devices can be effective, but can require significantly more operation time and planning to correctly install. Further, such fixation devices must be fixated in adjacent bone tissue by forcing the fixation devices into the adjacent bone tissue, which can cause damage to the adjacent bone tissue that will need to be surgically repaired.
One approach that has been tried to remove the need for bone cement is to put a porous ingrowth material on the implant that encourages bone ingrowth into and bonding with the pores of the material. The filling of the pores with bone material that bonds with the implant is an attractive solution, but the time necessary for sufficient bone ingrowth into the pores is a significant period during which the patient is unable to move the area where the implant is fixated. In the event that the patient moves or the implant otherwise manages to move during the bone ingrowth phase, there is also a possibility that the bone material in the pores will shear from the surrounding bone tissue and the pores will be filled with bone material that provides no fixation. In light of such risks, most implants that have fixating ingrowth material will still utilize bone cement or another fixation method, such as bone screws, to sufficiently fixate the implant following implantation.
What is needed in the art is a way to fixate orthopaedic implants in a patient's body that overcomes some of the previously described disadvantages.